The random insertion of introduced DNA into the genome of a host cell can be lethal if the foreign DNA happens to insert into, and thereby mutate, a critically important native gene. In addition, even if a random insertion event does not impair the functioning of a gene of a host cell, the expression of an inserted foreign nucleotide sequence may be influenced by position effects caused by the surrounding genomic DNA. In some cases, the nucleotide sequence is inserted into a site where the position effect is strong enough to suppress the function or regulation of the introduced nucleotide sequence. In other instances, overproduction of the gene product has deleterious effects on a cell.
For example, in plants, position effects can result in reduced agronomics, additional costs for further research, creation of additional transgenic events, and slower time to product. For these reasons, efficient methods are needed for targeting the insertion of nucleotide sequences into the genome of various organisms, such as plants, at chromosomal positions that allow desired function of the sequence of interest.